Engine valve-gear.



R. G. STEVENS.

ENGINE VALVE GEAR.

APPLICATION FILED JAN.25. 1913.

1,072,786, Patented Sept. 9,1913.

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UNITED sTATEs PATENT onnicn.

ROBERT C. STEVENS, 0F ERIE, PENNSYLVANIA.

ENGINE VALVE-GEAR.

Application filed January 25, 1913. Serial No. 744,203.

To all whom it may concern:

Be it known that I, ROBERT C. STEVENS, a citizen of the United States, residing at Erie, in the county of Erie and State of Pennsylvania, have invented certain new and Useful Improvements in Engine Valve- Gear; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters of reference marked thereon, forming part of this specification.

My invention relates to engine-valve-gear, and has for its object the provision of mechanism for operating the exhaust valves of that type of engine shown and described in U. S. Letters-Patent No. 1,033,280 issued July 23, 1912, to Skinner and Williams, which are adapted to be used either as a noncondensing engine or a condensing engine, as may be desired, by connecting or disconnecting the operating gear of the exhaust valves, whereby, when the vacuum in the exhaust pipe of the engine, when operating as a condensing engine, is broken, the ex haust valve of the engine will be started into operation automatically, and will continue to operate the engine as a non-condensing engine until the vacuum in the exhaust pipe is restored, when the operation of the exhaust valves will cease and they will remain closed, and the engine thereby will automatically become a condensing engine. The type of engine to which such a valve-gear is applicable, is fully shown and described in the above mentioned Letters- Patent, and is what is known as a central exhaust engine, viz :-an engine having exhaust ports located at the central portion of the cylinder, which central exhaust ports are covered and uncovered by the engine piston during its reciprocations, the vacuum in the exhaust being communicated to the cylinder at either end of the same, when the central exhaust ports are uncovered by the piston, to a sufficient degree to prevent ex cessive compression in the cylinder during the return stroke of the piston. When, however, the vacuum in the exhaust pipe is destroyed, and the engine is desired to be operated as a non-condensing engine, it is necessary to provide auxiliary exhaust ports and valves intermediate between the central exhaust ports and the ends of the cylinder,

Specification of Letters Patent.

Patented Sept. 9, 1913.

which auxiliary exhaust valves are only operated when the pressure in the cylinder has been relieved by the uncovering of the central exhaust ports by the piston, and said auxiliary exhaust valves remain open until the auxiliary ports are covered by the return stroke of the piston when they are closed, thus making it possible to operate the auxiliary exhaust valves, to open and close the same, when there is no pressure thereon.

The features of my invention are herein- Fig. 4c, is a diagrammatic View of my automatic valve gear.

In these drawings, A, indicates an engine cylinder, a, indicates auxiliary exhaust ports, A, indicates an auxiliary exhaust valve, A indicates the valve-stem of said valve, B, indicates the exhaust chamber, B, indicates the exhaust pipe thereof, b, indicates the central exhaust ports (see Fig. 2) and C, indicates the engine shaft, all of which parts are of usual and ordinary construction in steam engines of this type.

In carrying out my invention I secure upon the valve-housing D, of the valvestem A a support D, constructed of nonmagnetic material, and within this support D, upon the valve-stem A I secure a yoke E, of non-magnetic material, having a cylindrical portion E, embracing the -valve stem housing D, upon which cylindrical portion E, I place a spring F, adapted to maintain the auxiliary exhaust valve A, in a normally closed position, as shown in Fig. 1.

The cylinder E, is preferably provided with being provided with lateral extensions 71. To the side of the engine frame adjacent to the shaft C, I secure a brush support J, and on this brush support J, I ncn-rotatably secure brush holders K, adapted to hold brushes 7c, in a position adapted to contact with the lateral extensions h, of the conductor H, on the commuator H. Upon the brush support J, between the brush holders K, I also place a brush holder K, so that said brush holder K, may be rotated on the support J. For rotating or rocking the brush holder K, on the support J, I provide a pneumatic mechanism L, preferably of the diaphragm type, having a piston-rod or stem L, which is connected with an arm L on the brush holder K, and for operating the pneumatic mechanism L, I provide a pipe connection M, leading therefrom into the exhaust pipe B, of the engine. For operating the electro-magnet-ic device G, I provide an electric generator N, with an electric conductor N, leading from one pole of said generator to one of the poles of the electro-magnetic device G, and with another electric conductor N leading from the opposite pole of said generator N, to the oscillatory brush-lever L and from one of the stationary brushes in, to the opposite pole of the electro-magnetic device G.

In operation, when the engine is operating as a condensing engine the vacuum in the exhaust pipe B, is communicated to the pneumatic mechanism L, through the pipe M, and operates to draw the rod L, clownward, thereby raising the brush is, secured in the oscillatory brush holder K, out of contact with the conductor H, on the commutator H, thereby breaking the electric circuit from the generator N, through the electro-magnetic device G, and permitting the spring F, to retain the auxiliary exhaust valve A, in a closed position as shown in Fig. 1. When, however, the vacuum in the exhaust pipe B, is absent, the pneumatic mechanism L, is thereby released and the rod L, permitted to move upward thereby causing the brush 70, to contact with the conductor H, on the commutator H, thus restoring the circuit from the generator N, through the electro-magnetic device G, and

thereby operating the auxiliary exhaust valve A, and transforming the engine from a condensing engine into a non-condensing engine automatically.

Having thus fully described the construction and operation of my invention so as to enable others to utilize the same, what I claim as new and desire to secure by Letters- Patent is l. The combination in an engine valvegear, of an exhaust valve, a stem secured thereto, a spring adapted to maintain said to rotate inunison with said shaft, brushes adapted to contact with said commutator, an electric generator, an electric circuit leading from said generator to said electro-magnetic device, and to said brushes and a pneumatic mechanism communicating with the exhaust of the engine adapted to be actuated by vacuum to make and break said electric circuit, substantially as and for the purpose set forth.

2. The combination in an engine valvegear, of an exhaust valve, a stem secured thereto, a spring adapted to maintain said valve in a normally closed position, an electro-magnetic device connected to said valvestem, an engine-shaft, a commutator adapted to rotate in unison with said shaft, a continuous electric conductor on said commutator, lateral extensions on said conductor, brushes adapted to contact with said com mutator, an electric generator, an electric circuit leading from said generator to said electro-magnetic device, and to said brushes, and a pneumatic mechanism communicating with the exhaust of the engine adapted to be actuated by vacuum to operate said brushes to make and break said electric circuit, substantially as and for the purpose set forth.

3. The combination in an engine valvegear, of an exhaust valve, a stem secured thereto, a spring adapted to maintain said valve in a normally closed position, a solenoid coil, a core within said coil attached to said valve-stem, an engine shaft, a commutator on said shaft, an electric conductor on said commutator, a brush-holder support, an oscillatory brush-holder on said support, a brush secured in said holder adapted to contact with said commutator, a stationary brush-holder on said support, a brush secured therein adapted to contact with said commutator, a generator, an electric circuit between said generator through said brushes and commutator to said solenoid, a pneumatic diaphragm mechanism in communication with the exhaust of the engine, and rod and lever mechanism adapted to operate said oscillatory brush-holder to raise the brush secured therein out of contact with said commutator, substantially as and for the purpose set forth.

In testimony whereof I aflix my signature, in presence of two witnesses.

. ROBERT C. STEVENS. Witnesses:

H. M. STURGEON,

E. E. MYERS.

Copies of this patent may be obtainedfor five cents each, by addressing the Commissioner of Patents,

Washington, D. G. 

